Smelting or fusing metallic substances



Sept 2 ,1924, LSZ397 R.MOLDENKE SMELTING OR FUSING METALLIC SUBSTANCES Filed Dec. 1 [9225 3 Sheets-Sheet l l hVVENTDR A TTORNEY R. MOLDENKE SMEZLTING OR FUSING METALLIC SUBSTANCES Sept 2 9 192% LSQEZBQ? Filed Dec. 11 1922 3 Sheets-Sheet 5 1N VENTOR ATTORNEY Patented Sept. 2, 1924.

UNITED STATES 1,507,392 PATENT OFFICE.

RICHARD MOLDENKE, F WATCHU'NG, NE'l/V JERSEY.

SMELTING OR FUSING METALLIC SUBSTANCES.

Application filed December 11, 1922. Serial No. 606,045.

This invention relates to the smelting or fusing of metallic substances. and more particularly to the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resultingfrom the combustion of fluid and solid fuels. has for its object certain improvements in processes of this character.

In the United States patents of Bradley Stoughton, No. 1,117.274. patented Novem ber 17, 1914, and. No. 1,376,479, patented. May 3, 1921. processes of the character to which the present invention relates are dc scribed. The essential features of these proc essess'involve the use of as much fluid fuel as practicable to supply the heat required and the minimum quantity ofsolid fuel. Such processes are of particular importance in localities where solid fuel is scarce or expensive. In the practice of these processes. and the same is true of the present invention; any desirable form of fluid fuel may be used. either gaseous or liquid, as. for example, a combustible gas. either natural or generated. or pulverized fuel. but ordinarily oil is most available and satisfactory. Similarly, any desirable form of solid fuel may be used as. for example. coal or charcoal but ordi narily coke is generally used.

Heretofore in the practice of these processes. it has been customary to blow in the fluid fuel, usually oil, directly with the air blast. either in the same tuyeres in the usual position in cupola melting practice. or irist a little above this position. but always under or lower than the melting zone of the fur nace. that is. the zone of the furnace where the metallic substance fuses or melts. When melting iron. l: have found that while this practice produces hot molten metal. nevertheless the motion iron may be oxidized to such an extent as to ohiectionably nd injuriously affect the so-called life or the metal. lhis slight oxidation of molten The invention iron raises the freezing point of the molten metal as a result of the solution in the iron of an appreciable amount of an oxide of iron. In ordinary foundry practice, such molten iron, when thus slightly oxidized, has to be poured off quickly into molds, otherwise the metal will set in have been completely filled, thereby materially reducing the number of usable cast-- ings produced.

the gates before the molds I have discovered that hot molten iron can be produced without objectionable oxidation by heating the metal to near its melting point by heat resulting for the most part from the combustion of the fluid fuel and then raising the temperature of the metal to effect its fusion by heat resulting for the most part from the combustion of the solid fuel appropriately mixed with the metal.

Thus. my present invention involves the 1 application in different zones or parts of the cupola or other furnace of the heat resulting respectively from the combustion of the fluid fuel and the solid fuel. to-the end that the heat resulting combustion of the fluid fuel be utilized to reheat the metallic substance, such as iron, while the heat resulting from the combustion of the solid fuel effects the melting or fusion of the metallic substance.

In carrying out my invention, l introduce the heat resulting of the fluid fuel into the furnace at a pointabove the melting zone of the metallic substance. Inv my preferred fuel. such as oil. is burned in an independent burner or apparatus and the hot gaseous products resulting therefrom are appropriately conducted to and into the furnace above its melting zone. products serve to preheat the metallic substance, such as iron,

separate perature. In my preferred practice, the zone in which this preheating take place contains from the from the combustion practice. the fiuid- These hot gaseous and to bring it to a temperature approaching its melting teminsuficient combustion-supporting gas, such as air. oxygen or the like, to support active combustion of the SOllQ Iuel mixed with the metallic substance. Having been brought to near its melting temperature, the metallic substance next passes into the melting zone of the furnace where itstemperature is raised to effect the desired fusion of the metal heat resulting from t solid fuel admixed with the metallic sub stance. fr. melting acne, active core he cornhustion of the burnerQQ and the flue 18, or

bustion of the solid fuel is, insured by introducing into this zone through appropriate tu'yeres, or the like, a surplus of air, or other appropriate combustion-supporting g The following description, taken in conjunction with the accompanying drawings, will make the invention and the manner of carrying it out in practice clear to those skilled in the art. In the drawings Fig. 1 is a sectional elevation of a cupola furnace adapted for the practice of the invention;

Fig. 2 is a diagrammatic view on a reduced scale of the cupola of Fig. 1 operatively connected with an independent burner for the fluid fuel;

Fig. 3 is a sectional plan view of the same on the line 33 of Fig. 2;

Figs. 4 and 5 are sectional elevations of modified constructions of cupolas adapted for the practice of the invention; and

Figs. 6 and 7 are detailed views of a peep hole and peep hole cover respectively.

The cupola furnace illustrated in Fig. 1 comprises a steel shell 10 and a fire-brick lining '11 appropriately supported on pillars "2. The usual tap holes or spouts 13 and 14 are provided for tapping ofi' the fused metal and the slag or cinder respectively. A series, of tuyeres 15 communicate with the interior'of the 'cupola near the lower part thereof. These tuyres arefsupplied with air or similar combustion-supporting gas .through a wind box 16 in communication with an air pipe 17.

A brick flue 18 surrounds the cupola at an appropriate distance above the tuyeres 15. A series of ports 19, see Fig. 3, provide I communication between the flue Bend the interior of the cupola. The flue 18 is con nected to the 'combustion.chamber of the, gazixiliary and independent fluid fuel burner The burner 20 is preferably a fire-brick lined structure provided with a plurality of fluid fuel burners. As illustrated in Fig. 3, these fluid fuel burners consist of pipes 21 for supplying an appropriate fluid fuel such, for example, as crude oil, fuel oil, pulverized fuel, tar, or the like, and pipes 22 for supplying compressed air. A wind box 23 supplied with air from a fan through pipe 24 is associated with each fluid fuel burner and serves to introduce into the combustion chamber of the burner 20 a regulatable blast of air or similar combustion-supportingygas. Man holes 25 and 26 are provided at the top and end respectively of burner 20. Peep-holes may be provided in the conduit hetween the combustion chamber or" the the due 18 opposite the ports 19, or at any desired point in the combination of apparatus. I

The peephole, or arrangement for observingoonditions in the interior of the cupola or any part of it's appurtenances, consists of a small opening 27 through the shell and firebrick lining within range of a snugly fitting peep-hole c0VeI'28 adapted to be revolved in either a clockwise or counter clockwise direction. The peep-hole cover contains a peep-hole 29 and an opening 30 so positioned that they may be superposed over the opening 27 in the furnace lining by merely turning the peep-hole cover in one direction or the other. contains a transparent heat resisting material, such as mica, and when properly superposed over the opening 27 enables one to view the interior of the apparatus from close range. The opening 30 contains no obstruction and when properly superposed over the opening 27 allows ,the flame from the apparatus to shoot out therebyenabling the operator to accurately observe the character of the combustion taking place in the apparatus. Any obstruction lodging in opening 27 or ports 19 may be removed by insertiug a rod or poker through the opening 30. it will be understood, however, that when no observations are beingmade the peep-hole cover may be turned so as to close the opening 27 and prevent admission of air to the interior of the apparatus.

The burner 20 may be fired similar to any ordinary fluid burning furnace. The man holes 25 and 26 may be opened to allow sufficient air to enter the burner to supporter-- dinary combustion. Oil from pipe 21 may be atomized by compressed air from pipe 22 and ignited. When the burner walls become red.rot and will keep the atomized oil alight, the man holes are closed and proper combustion is brought about and maintained by controlling the amount of air supplied from a fan. not shown.-to the wind box 23. The hot products of combustion from the burner 20 pass into the flue-l8 and thence to the cupola through the ports 19. An air blast is then forced into the cupola through the tuyeres 15 near the bottom thereof and supports the combustion of the solid fuel. which, in turn, supplies suflicient additional heat to melt and superheat the metal for pouring 'into moulds.

'lhe cupola is charged periodically with mixtures of pig or scrap metal. fuel and, if necessary, also, with slag-forming materials. I prefer to charge the cupola with alternate layers of solid fuel and pig or scrap metal. As the apparatus continues in operation charges of solid fuel and metal pass progressively downward in the cupola, first through the oil-heat position, or preheating zone, where the solid fuel and metal is raised by the hot products of combustion of the fluid fuel to a temperature justunder the melting temperature of the metal, and then into the melting some where the metal The peep-hole 29 Ill with the gaseous products from the melting zone. The combustion of the fluid fuel without surplus air involves so regulating the combustion of the fluid fuel that the resulting hot gaseous products of combustion contain little and preferably no. surplus of combustion-supporting gas. Vhere the optimum advantages of the invention are realized, as in mypreferred practice, these conditions and factors are so regulated and correlated that the preheating zone of the furnace contains insufiicient combus-' tion-supporting gas to support active 'combustion of the solid fuel as it passes through this zone.

When water vapor comes into contact with solid iron there is formed a coat of iron oxide corresponding somewhat to rust. Asa this coated, or rusted, solid iron descends into the melting zone of the furnace, there is either the chance of a reduction of the iron oxide by the carbon monoxide (CO) gas on the way down, of the iron the oxide is in a measure cared for by the slag, or else the amount is so little that it does not affect the product any more than rust does in ordinary melting. In other words, probably none of the oxide gets into the molten metal, or only a negligible amount, so that the freezing point will not be materially affected.

On the other hand, when water vapor comes into contact with the drops of molten metal in the forming, the melting metal being in contact with the water vapor an appreciable time before the drop falls off the still solid piece of iron, there is a chance for the continual solution of the iron oxide formed on the surface of the forming drop of molten metal and thus a comparatively large amount of dissolved iron oxide in the metal raises the freezing point. The result is that very hot molten metal, by setting too fast, will not give proper castings when poured into molds. In the melting zone proper there is no opportunity for a reduction of iron oxide by carbon monoxide gas, as may take place higher up in the furnace. There is no carbon monoxide gas in the melting zone, or in any event there should be little, if any. such gas that low down in the furnace. The carbon monoxide gas is formed higher up and at these higher levels may possibly reduce rust to metallic iron. It is for these reasons that, in accordance with my present invention, the liquid fuel is introduced above the melting zone of the furnace. What I aim to achieve is to prevent the formation of iron oxide by water vapor where this oxide cannot be reduced, but on the other hand remains and dissolves in the molten metal with the hereinbe'fore mentioned disadvantages.

I claim:

1. The improvement in the process of a furnaceto the action or else in the melting smelting -or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels, which comprises so adjusting or arranging the supply/ of fluid and solid fuels and the air or other combustion-supporting gas or gases that the products of combustion of the fluid fuel shall not come in contact with the molten metal.

2. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in the combustion. of fluid and solid fuels, which comprises supplying the heat of combustion of fluid fuel to an appropriate mixture of metallic substance and solid fuel and thereafter bringing the metallic substance to an appropriate molten condition by heat depived solely from the combustion of the solid uel.

of heat resulting from 3. The improvement in the process of. I

smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels, which comprises supplying the heat of combustion of fluid fuel without surplus air to an appropriate mixture of metallic substance and solid fuel, and thereafter bringing the metallic substance to an appropriate molten condition by heat derived soley from the combustion of the solid fuel in he presence of an appropriate amount of air.

4. .The improvement in the process of smelting or fusing metallic substances. in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels, which comprises supplying the heat of combustion of fluid fuel to an appropriate mixture of metallic substance and fuel in a preheating zone, and thereafter bringing the metallic substance to an appropriate molten condition in a melting zone by heat derived solely from the combustion of the solid fuel.

5. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels, which comprises supplying the heatof combustion of fluid fuel without surplus air to an appropriate mixture of metallic substance and fuel in a preheating zone, and thereafter bringing the metallic substance to an appropriate molten condition in a melting zone by heat derived solely from the combustion of the solid fuel in the presence of anappropri ate amount of air.

6. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heatresulting from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel through a preheating zone maintained for the most part by the combustion of fluid fuel at a temperature slightly below the melting temperature of the metallic substance and then passing the metallic substance thus preheated to a temperature approaching its melting temperature through a melting zone maintained for the most part by the combustion of said solid fuel at a temperature above its meltingtemperature.

7. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel through a preheating zone maintained for the most part by the combustion of fluid fuel without surplus air at a temperature slightly below the melting temperature of the metallic substance and then passing the metallic substance thus preheated to a temperature approaching its melting temperature through a. melting zone maintained for the most part by the combustion of said solid fuel in the presence of an appropriate amount of air at a temperature above the melting temperature of the metallic substance.

8. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel through a preheating zone and a melting zone, said preheating zone deriving its heat for the most part from the combustion of liquid fuel and said melting zone deriving its heat for the most part from the combustion of said solid fuel.

9. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel through a preheating zone and a melting zone, said preheating zone deriving its heat for the most part from the combust-ion of liquid fuel without surplus air and said melting zone deriving its heat for the most part from the combustion of said solid fuel in the presence of an appropriate amount of air,

ll). The improvement in the process of smelting or fusing metallic sub-stances in whici the metallic substance is subjected of heat renilting increase from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel through a preheating zone whose temperature approaches but does not reach the melting temperature of the metallic substance and through a melting zone whose temperature exceeds the melting temperature of the metallic substance, said preheating zone deriving its heat for the most part from the combustion of liquid fuel and said melting zone deriving its heat for the most part from the combustion of said solid fuel.

111 The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel through a preheating zone whose temperature approaches but does not reach the melting temperature of the metallic substance and through a melting zone whose temperature exceeds the melting temperature of the metallic substance, said preheating zone deriving its heat for the most part from the combustion of liquidfuel without surplus air and said melting zone deriving its heat for the most part from the combustion of said solid fuel in the presence of an appropriate amount of air.

12. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises bringing the metallic substance to substantially its melting temperature by heat resulting for the most part from the combustion of fluid fuel and then effecting the fusion, of the metallic substance by heat resulting for the most part from the combustion of solid fuel appropriately admixed therewith.

13. The improvement in the process of smelting or fusing metallic substances in which the metallic'substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels Which comprises bringing the metallic substance to substantially its melting temperature by heat resulting for the most part from the combustion of fluid fuel without surplus air and then efiecting the fusion of the metallic substance by heat resulting for the most part from the combustion in the presence of an appropriate amount of air of solid fuel appropriately mixed with the metallic substance.

14. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in furnace to the action heated for the most part from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately with solid fuel downwardly through a preheating zone and a melting zone of the furnace, said preheating zone being heated for the most part by the hot gaseous products resulting from the combustion exteriorly of the furnace and its direct appurtenances of fluid fuel and said.melting zone being heated for the most part by heat furesu1 ltingfrom the combustion of said solid 15. The im rovement in the process of smelting or using metallic substances in which the metallic substance is subjected in a furnace to the action of heatresulting from the combustion of fluid and solid fuels which comprises progressively passing the metallic substance appropriately mixed with solid fuel downwardly through' a preheating zone and a melting zone of the furnace, said .preheating zone being by the hot gaseous products resulting from the combustion exteriorly of the furnace and itsdirect appurtenances of fluid fuel without excess of air, and said melting zone being heated for the most part by heat resulting from the combustion of said solid fuel in the presence of an appropriate amount of air.

16. The im rovement in the process of smeltin or using metallic substances in which t e metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises progressively passing alternate layers of the metallic substance and solid fuel downwardly through a preheating zone and a melting zone, subjecting the metallic substance as it passes through the preheating zone to heat resulting for the most part from the combustion of fluid fuel, said preheating zone containing insufficient combustion supporting gas to support active combustion of said solid fuel as it passes therethrou h, and fusing the preheated metallic suistance in said melting zone by heat resulting for the most part from the active combustion of said solid fuel in the presence of an appropriate amount of air.

17. The 1m rovement in the process of smeltin or using metallic substances in which t e metallic substance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises progressively passing alternate layers of the metallic substance and solid fuel downwardly through a preheating zone and a melting zone, subjectin the metallic substance as it passes throug the preheating zone to the hot gaseous products resulting from the combustion exteriorly of the furnace and its direct appurtenances of fluid fuel, said preheating zone containing insufficient combustion supporting gas to support active combustion of said solid fuel as it passes therethrough, and fusing the preheated metallic substance in said melting zone by heat resulting for the most part from the active combustion of said solid fuel in the presence of an appropriate amount of air.

18. The improvement in the process of smelting or fusing metallic substances in which the metallic substance is subjected in a furnace to the action of heat resultin from the combustion of fluid and solid fuels which comprises bringing the metallic sub stance to substantially its melting temperature by the hot gaseous products resulting from the combustion exteriorly of the furnace and its direct appurtenances of fluid fuel, and then effecting the fusion of the metallic substance by heat resulting for the most part from the combustion of solid fuel appropriately mixed therewith.

19. The improvement in the process of smelting or fusing metallic substances in which the metallicfsubstance is subjected in a furnace to the action of heat resulting from the combustion of fluid and solid fuels which comprises bringing the metallic substance appropriately mixed with solid fuel to substantially its melting temperature by the hot gaseous products resulting from the combustion exteriorly of the furnace and its direct appurtenances of fluid fuel, maintainmg insufficient combustion-suppplrting gas in contact with the solid fuel a ixed wlth the metallic substance while the latter is undergoing the aforementioned preheating to sup-port active combustion of said solid fuel, and subsequently effecting the fusion of the metallic substance by heat resulting for the most part from the active combustion in the presence of an appropriate amount of air of said solid fuel.

In testimony whereof I aiiix my signature.

RICHARD MOLDENKE. 

